Chuck



G. W. COOK CHUCK Filed May 24,* 1944 ma MM BeBa/VM@ u" Y D -l 6. D 1 m w ma. Mm N f V M l ../Ta W HI ab l a a `22A /32 @TYEZZv aaa x A|||| Mm.

Patented Feb. 26, 1946 CHUCK George'W. Cook, Los Angeles, Calif.,ga`ssignor of'v `n'i'netyfpcr centl to Lloyd W. Miller, Glendale;

Calif.

. ApplleationMay 24, 1944.Serial`No. k537,041 (o1. 27s-s2) My present invention hasto do with chucks of ,the typeknown as quickechangerchucks. The generalpurpose of the, invention is to provide an improved chuckofA the quick change type which is `simple in construction and .operation and, Particularly, which holds the tool adapter or collet firmly and `accurately in its operativezposition and in which the release of the adapter and the tool is free and instantaneous.

The invention will .be more readilyv understood from the following v.detailed description of an illustrative design 'embodying` my improvements, referencebeing hadto the accompanying `drawingiin which,

Fig. 1 is a longitudinalcentral section showing the chuck mits-operative position with the tool inserted;

Fig. `2 is a similar sectionshowing the tool released, and

Fig. 3 `is a cross section .taken on line 3-3 of Fig. 1.

In the drawing numeral I designates a 4chuck lbody which may bemounted on the spindle of any machine tool, such as the spindle of a `drill press; bore .I:|, or any other attachment means, being designed suitably ,for attachment to the spindle. Assuming that the-chuck body is mounted on theA lower `end of adrill press spindle, the parts will be described 4in'vertical position. The lower end of chuck body I0 ,isprovided with a` downwardly opening tapered and preferably conical socketv I2, preferably of 4afsuiciently large `angle of taper that thesimilarly tapered adapter l; 3 will not be frictionally. vseized in the tapered ore. 4and tapered bore I2 is notdepended upon for the rotative driving` of the adapter andthe tool; it is rather desired that the conical engagement be freely releasable so that the adapter and tool, when released,` will immediately drop out of the conical bore. Consequently, a rotative driving connection is` provided inthe formofnon-circular parts; for instance, asquare driving lug I5 on the upper end of adapter I3 entersa similarly square/driving bore I 6 ,in bodyilll at the upper `end-of tapered bore i lf2. Any .other :suitable driving engagementmay be I, used; forv instance the tapered bore ,and adapter could be non-circular -(e. g.;square) incross-section.

.AV .circular groove'Y IB 'is formed in. the conical surface Ill v'of'V adapter I3, -thezibottom. face 18a of the groove being, conical: in. form, tapering downwardly, :andthe-'conical angle being preferably greater than the conical angle of bore I 2 and adapter surface I9. When the adapter is in- Gripping. engagement between adapter I3 serted, `as shownin Fig. 1, surface 18a .is engaged by the flat ends of pinsv 2li which are slidably mounted inbody II) in bores 2.I oniupwardly and inwardly inclined axes 22 which are at right angles to the conical grooveJfa-ce lI8`a. As shown in the drawing, merely for convenience of illustration, twooppositely disposed pins are illustrated. Three, symmetrically arranged about' lthe axis, are preferred; andgenerally speaking, while asingle pin will` perform. thefunctions which are here described, a plurality insymmetric arrangementis preferred. Pins 20 have heads 2,3 at their outer ends, and light coil springs 2.1i` are confined between heads 23 and recessed shoulders 25 in body IIB. Springs 24 tend'at all times` to ,move pins 20 outwardly,A from, the position of Fig. 1 to the `position of Fig. 2, and thus to. disengage the inner ends Vof the pins from conical surface I8a and to allow vadapter I3 to drop freely out of the chuck body.

Locking pins 20 are forcedinwardlyto the.pos'

tion of Fig. 1 by the action `of' internal conical surface 25 which forms the lower part of the interior bore of an. externalA operating' member 26, generally cylindric in form.. Member 26 is urged upwardly, and normally held inthe upper position shown in Fig. 1, by aV heavy spring` 21 which is confined between body shoulder 28 and the upper 4shoulder 29 on memberZB. The .ring shown at `3l! at the upper end of thebody merely typies some means of limiting the upwardmovement of 26 when that member is allowed tomove upward and no adapter I3 is presentin the chuck to limit the inward movementsof pins 2.0;

The tool which is held. in adapter I3 may be a tool of any character, here vshown as a twist drill 35; and the tool may be mounted in the adapter by any suitablemeans, vhere shown as a split tapered sleeve v35. Toolsof different sizes may be mounted in adaptersA of standardized size by using sleeves 36 of proper internal dimensions.

Although I prefer to use the described-arrangement, embodying an adapter which isa piece separate from the tool. ritself `and adapted to `take tools of various sizes, it will be understood `that the adapter may be a partof the toolitself.

When it 4is 'desired to insert an adapter and its tool into the chuck, external sleeve 26 ispulled `down to the position of Fig. 2.V When that `is done, springs 24 act to :move 'pins 20 out to the positions shown in that figure, so that the pins do not haveto be moved-outwardly bythe .subsequent `insertion Lof 'thecadapten The..fadapterpis then inserted to the position shown in Fig. 1, and, upon subsequent release of outer sleeve 26, spring 21 forces 26 up to the position of Fig. 1 and forces pins 20 inwardly and upwardly with considerable pressure against the downwardly'tapering face I8a. Due to the angles at which pins 20 are placed, and the angle of face I8a, the inward force exerted through thepins along their inclined longitudinal axes has an upwardly directed component which forces the adapter upwardly and thus presses its conical face I9 upwardly into snug close engagement with conical bore I2. And in this connection, the fact that the downwardly Vtapering angle of seat surface [8a is greater than the upwardly tapering angle of bore I2 and adapter surface I9, is of some importance; the pressure which is exerted axially through the pins not only has an upward component with reference to the vertical axis of the adapter, but also has an upward component with reference tothe opposite Wall of tapered bore I2. 'Thus, when the parts are in the position shown in Fig. 1, the adapter is held tightly up into its conicalseat and the tool35 is thus rigidly and accurately heldl in concentric alinement with the chuck body and with the spindle on which it is mounted. It is further to be noted that when the parts are in the position of Fig. 1, any force which tends to move the adapter and tool downwardly, cannot movel the actuator sleeve 26downwardly to releasethe adapter from the chuck. That self locking feature is due to the fact that the semitaper angle of conical surface 25 (the angle between the `central axis and an element of that conical surface) is less than, rather than more than, the complement of the acute angle between the central axis and the axis 22 of a pin 20. Outward movement of pin 20 on its axis 22 tends to .move actuator sleeve up, rather than down.

To release the Vadapter with its tool, it is only necessary to pull downwardly on the external operating sleeve 26. Immediately that sleeve is moved to the position in Fig. 2, springs 24 act to retract locking pins 20 so that the adapter and tool then fall freely out of the chuck. As soon as the adapter has'fallen to about the position of Fig. 2, operating sleeve 26 maybe released if desired, and the operator may then catch adapter I3 in the same hand which he has used for pulling sleeve 26 down. In the Aposition of the parts shown in Fig. 2, if sleeve 26 is then released, the subsequent inward movements of pins 20 will cause the bevels 20a at their inner ends to engage the conical adapter surface I9 above the seat surface I8a; and the inwardly pressed movements of the pins will thus tend to force the adapter out rather than to retain it in the chuck. In any case,4 and regardless of how the operation is performed, it is to be noted that`when external operating sleeve 2E is lowered, locking pins 20 are moved out by their springs 24 and do not have to be moved out by exerting a downward pull on the adapter. This feature is of some importance in making quick changes, as there are thus no parts of the device which are liable to stick and, require the application of manual force to remove the adapter and tool.

So far as the rotary driving connection between chuck and adapter is concerned, the adapter may be inserted in any one of several different positions. With a square driving lug, that number is four. To facilitate that indifferent insertion of the adapter, the easiest manner of forming a number of recesses in the adapter face :or engagementby a pin 20 or by a number of pins, is to form a circular groove as shown. Functionally, however, the circular groove may be conof being simple and easy of construction as well` as of operation. It is especially adapted, although of course not limited, to being made in very small sizes and for use on portable power tools where lightness, simplicity and ease of operation are especially desirable.

I claim:

l. In a quick-change chuck, the combination of a chuck body having an adapter receiving bore which tapers inwardly fromthe outer end of the body, a tapered adapter receivable in the bore, a recessed locking face in the tapering surface of the adapter, said face tapering longitudinally of the adapter in a direction opposite to the taper of the adapter surface, a locking pin mounted in the chuck body'to slidingly project its inner end into the tapered bore and to engage the recessed locking face `of the adapter, the axis of sliding movement of the pin inclining toward the l central body axis and toward the inner end of the body, the outer end of the pinL projecting beyond the outer surface of the body, an outer operating sleeve slidable longitudinally on the body and having at its outer end an internal bore which tapers toward the outer end of the sleeve, said tapered bore adapted to engage the projecting end of the pin so as to force the pin inwardly in the body by virtue of movement of the operating sleeve' toward the inner end of the body and so as to release the pin for outward movement by virtue of movement of the sleeve toward the outer end of the body, and a spring 'acting between the body and the sleeve tending' to move the sleeve toward the inner end of the body.`

2. In a quick-change chuck, the combination of a chuck body having an adapter receiving bore which' tapers inwardly from the outer end of the body, a tapered adapter receivable in the bore, a recessed locking face in the tapering surface of the adapter, said face taperingylongitudinally of the adapter in a direction opposite to the'taper of the adapter surface, a locking pin Vmounted in the chuck body to slidingly project its inner end into the tapered bore and to .engage the recessed locking face of the adapter, the axis of sliding movement of the pin inclining toward the central body. axis and toward the inner end of the body, the outer end of the pin projecting beyond the outer surface of the body, an outer operating sleeve slidable longitudinally on therbody and having at its outer end an internal bore which tapers toward the outer end of the sleeve, said tapered bore adapted to engage the projecting end of the pin so as to force the pin inwardly in the body by virtue of movement of the operating sleeve toward the inner end of thev body and so as toV release the pin for outward movement by virtue of movement of the sleeve toward the outer end of the body, and a spring acting between the body and the sleeve tending to move the sleeve toward the inner end of the body, the half-taper anglev of the bore in the sleeve being less than the complement of the acute angle between the pin axis and thecentral axis of the body, S70 that outward movement of the pin tends to move ,the sleeve toward the inner end. of the body.

GEORGE W. COOK. 

